SpringBoot - Request域，Session域，Application域，Cookie域 获取与添加数据

1.向Request域添加与获取数据的方式    SpringMvc - @ModelAttribute注解

方式1 HttpServletRequest 添加与获取数据

    @RequestMapping(value="meta")
    public void meta(HttpServletRequest request){
        //添加数据
        request.setAttribute("user",new Object());
        //获取数据
        Object user = request.getAttribute("username");
    }

方式2 Model 添加与获取数据

    @RequestMapping(value="meta")
    public void meta(Model model){
        //添加数据
        model.addAttribute("user", new Object());
        //获取数据
        Object user = model.getAttribute("user");
    }

方式3 ModelMap 添加与获取数据

    @RequestMapping(value="meta")
    public void meta(ModelMap modelMap){
        //添加数据
        modelMap.addAttribute("user",new Object());
        //获取数据
        Object user = modelMap.getAttribute("user");
    }

方式4 @RequestAttribute注解

    @RequestMapping(value="/arrtibuteTest")
    public void arrtibuteTest(@RequestAttribute(value="username") String username){
        ... 
    }

2.向Session域 添加与获取数据的方式

方式1 HttpSession 添加与获取数据

    @RequestMapping(value="meta")
    public void meta(HttpSession httpSession){
        //添加数据
        httpSession.setAttribute("user",new Object());
        //获取数据
        Object user = httpSession.getAttribute("user");
    }

方式2 HttpServletSession 添加与获取数据

    @RequestMapping(value="meta")
    public void meta(HttpServletRequest request){
        HttpSession session = request.getSession();
        //添加数据
        session.setAttribute("user",new Object());
        //获取数据
        Object user = session.getAttribute("user");
    }

3.向Application 添加与获取数据

    @RequestMapping(value="meta")
    public void meta(HttpSession httpSession){
        ServletContext servletContext = httpSession.getServletContext();
        //添加数据
        servletContext.setAttribute("user",new Object());
        //获取数据
        Object user = servletContext.getAttribute("user");
    }

4.添加Cookie与获取Cookie

    @RequestMapping(value="meta")
    public void meta(@CookieValue("userSessionId")String userSessionId,HttpServletRequest request,HttpServletResponse response){
        //添加Cookie
        Cookie cookie = new Cookie("userSessionId","JSESSIONID");
        response.addCookie(cookie);
        //根据name 获取一个Cookie
        System.out.println(userSessionId);
        //获取所有Cookie
        Cookie[] cookies = request.getCookies();
    }